This invention relates to liquid treatment apparatus, and more particularly to the control of the captive pressurized air volume in liquid treatment tanks. Control valves using the position of a float in a liquid being treated do not always operate reliably when the liquid is being treated at a relatively high pressure (e.g. above 50 psi). Prior art valves of this type frequently sputter air and the liquid being treated when they vent the treatment tanks to the atmosphere. Also, when the float itself is located at or closely adjacent the level of a liquid being treated, currents and movement of the liquid may interfere with the movement of the float and cause the control mechanism to malfunction; short cycling of a pressure pump activated by the control mechanism may also occur.
Accordingly, it is an object of this invention to provide improved liquid treatment apparatus and controls therefor.
Another object is to provide float controls for liquid treatment apparatus in which the float itself is located a sufficient distance above the surface of the liquid to prevent currents and movement of the liquid from interfering with the operation of the float.
An additional object is to provide controls for a pump that pressurizes a tank that prevent short cycling of the pump.
A further object is to provide pressurized liquid containing tanks with controls that facilitate detection and repair of leaks and malfunctioning components.
Another object is to provide a float control valve arrangement that flushes out a pipe that brings liquid to the float.
A further object is to provide a float control valve for large tanks that can be easily changed to operate at different liquid levels in such tanks.
An additional object is to prevent damage to liquid level controls during shipment of the apparatus in which the controls are used.
Another object is to provide for the easy replacement of float control valves in the field.
A further object is to provide the pressure control line, pressure gage and float valve assembly of a liquid treatment tank with pressure through a drop pipe in a way that isolates the pressurized air space in the tank from these components so as to prevent a leak or failure of any of these components from causing the system to shut down as a result of loss of air pressure in the tank.
A further object is to provide liquid level float control valves that are durable, economical, easy to use and to maintain and to repair, and which do not possess defects found in similar prior art float valves.
Other objects and advantages of the liquid treatment controls incorporating this invention will be found in the specification and claims and the scope of the invention will be set forth in the claims.